Mainland media reported that the police were treating the incident - which happened about 6.40pm on Monday at the Shanghai Shooting and Archery Sport Centre in Minhang District but was only publicly revealed yesterday - as a criminal case and have placed Chen Xiaoyi in custody. Security officials have also sealed off the pair's dormitory.

'A teammate of Chen asked to look at a defective bullet that had failed to fire in their previous training session. He loaded the bullet, which he thought was a dud, into a gun and began playing and joking with Chen,' reported the Shanghai Daily.

But the gun was fired at close range and the bullet 'was accidentally shot into Chen's belly', it quoted police as saying. Doctors said the bullet had severed a major artery and despite Chen being 'young and healthy', attempts to save him failed.

According to mainland sports ministry regulations, shooters must submit all ineffective bullets they find on the ranges to coaches for 'instant disposal'.

An investigation has been launched into the tragedy, which has sparked calls for already strict regulations at China's amateur shooting clubs to be tightened further.

The government-run Shanghai Municipal Sports Administration called an emergency meeting yesterday morning with the city's police authorities to 'strengthen the management of firearms held by the shooting team', a brief statement issued by the government said.

A spokeswoman from the city's sports authority declined to give any further details of the meeting last night, but it is understood officials are scrutinising events which appear to show the two team members breached strict security rules, which ban competitors from handling ammunition and firearms outside of supervised training sessions.

Meanwhile, a member of the State Sports General Administration - the country's top sports authority - flew to Shanghai to join the investigation.

Zhang Shan, the 1992 Olympic gold medallist in skeet shooting - the country's most celebrated markswoman - said she was 'dumbfounded' by the tragic accident and cast doubt over security and safety procedures at the training centre.

'I have never heard of anything even close to this,' Zhang told the Mirror newspaper. 'Every Chinese shooter is told not to play with a gun under any circumstances on the very first day of his or her shooting career. It's a basic of the sport.'

China's skeet shooting team are one of the best in the world and it is likely Chen - like his teammates in the reserve Shanghai squad - was vying for a place at next year's Beijing Olympics.

The young marksman's death was announced on the same day the mainland media celebrated the four gold, one silver and one bronze medal won at the ongoing Asian Shooting Championships in Kuwait.

A year ago, the Beijing government launched a crackdown on shooting clubs and ranges, closing four of the eight in operation, in what it said was part of the 2008 Olympic security preparations.

Critics said the early December 2006 crackdown would affect the country's national squad - who won four shooting golds at the 2004 Athens Olympics - and claimed the closures were further fallout from a scandal in the capital's shooting fraternity. Police arrested and charged a member of the Beijing shooting team after a gun went missing in October 2006.

The latest incident follows a tragedy two years ago in Liaoning province where a female provincial shooting team member was blinded by a stray bullet fired from a teammate's rifle.